Temp files should be deleted when an exception is thrown (#327)

If an exception is thrown while writing data, instead of letting the developer handle this situation gracefully, Spout can attempt to delete all the temporary files that were created so far, as well as the output file as it won't be completed and therefore corrupted.

src/Spout/Writer/AbstractWriter.php

@@ -4,6 +4,8 @@ namespace Box\Spout\Writer;
 
 use Box\Spout\Common\Exception\IOException;
 use Box\Spout\Common\Exception\InvalidArgumentException;
+use Box\Spout\Common\Exception\SpoutException;
+use Box\Spout\Common\Helper\FileSystemHelper;
 use Box\Spout\Writer\Exception\WriterAlreadyOpenedException;
 use Box\Spout\Writer\Exception\WriterNotOpenedException;
 use Box\Spout\Writer\Style\StyleBuilder;
@@ -199,13 +201,23 @@ abstract class AbstractWriter implements WriterInterface
      * @return AbstractWriter
      * @throws \Box\Spout\Writer\Exception\WriterNotOpenedException If this function is called before opening the writer
      * @throws \Box\Spout\Common\Exception\IOException If unable to write data
+     * @throws \Box\Spout\Common\Exception\SpoutException If anything else goes wrong while writing data
      */
     public function addRow(array $dataRow)
     {
         if ($this->isWriterOpened) {
             // empty $dataRow should not add an empty line
             if (!empty($dataRow)) {
-                $this->addRowToWriter($dataRow, $this->rowStyle);
+                try {
+                    $this->addRowToWriter($dataRow, $this->rowStyle);
+                } catch (SpoutException $e) {
+                    // if an exception occurs while writing data,
+                    // close the writer and remove all files created so far.
+                    $this->closeAndAttemptToCleanupAllFiles();
+
+                    // re-throw the exception to alert developers of the error
+                    throw $e;
+                }
             }
         } else {
             throw new WriterNotOpenedException('The writer needs to be opened before adding row.');
@@ -346,5 +358,24 @@ abstract class AbstractWriter implements WriterInterface
 
         $this->isWriterOpened = false;
     }
+
+    /**
+     * Closes the writer and attempts to cleanup all files that were
+     * created during the writing process (temp files & final file).
+     *
+     * @return void
+     */
+    private function closeAndAttemptToCleanupAllFiles()
+    {
+        // close the writer, which should remove all temp files
+        $this->close();
+
+        // remove output file if it was created
+        if ($this->globalFunctionsHelper->file_exists($this->outputFilePath)) {
+            $outputFolder = $this->globalFunctionsHelper->dirname($this->outputFilePath);
+            $fileSystemHelper = new FileSystemHelper($outputFolder);
+            $fileSystemHelper->deleteFile($this->outputFilePath);
+        }
+    }
 }